Posted on 11/16/2005 3:40:35 AM PST by snarks_when_bored
* 14:02 15 November 2005
* NewScientist.com news service
* Gaia Vince
A new microscope sensitive enough to track the real-time motion of a single protein, right down to the scale of its individual atoms, has revealed how genes are copied from DNA – a process essential to life.
The novel device allows users to achieve the highest-resolution measurements ever, equivalent to the diameter of a single hydrogen atom, says Steven Block, who designed it with colleagues at Stanford University in California.
Block was able to use the microscope to track a molecule of DNA from an E.coli bacterium, settling a long-standing scientific debate about the precise method in which genetic material is copied for use.
The molecular double-helix of DNA resembles a twisted ladder consisting of two strands connected by “rungs” called bases. The bases, which are known by the abbreviations A, T, G and C, encode genetic information, and the sequence in which they appear “spell out” different genes.
Every time a new protein is made, the genetic information for that protein must first be transcribed from its DNA blueprint. The transcriber, an enzyme called RNA polymerase (RNAP), latches on to the DNA ladder and pulls a small section apart lengthwise. As it works its way down the section of DNA, RNAP copies the sequence of bases and builds a complementary strand of RNA – the first step in a new protein.
“For years, people have known that RNA is made up one base at a time,” Block says. “But that has left open the question of whether the RNAP enzyme actually climbs up the DNA ladder one rung at a time, or does it move instead in chunks – for example, does it add three bases, then jump along and add another three bases.
Light and helium
In order to settle the question, the researchers designed equipment that was able to very accurately monitor the movements of a single DNA molecule.
Block chemically bonded one end of the DNA length to a glass bead. The bead was just 1 micrometre across, a thousand times the length of the DNA molecule and, crucially, a billion times its volume. He then bonded the RNAP enzyme to another bead. Both beads were placed in a watery substrate on a microscope slide.
Using mirrors, he then focused two infrared laser beams down onto each bead. Because the glass bead was in water, there was a refractive (optical density) difference between the glass and water, which caused the laser to bend and focus the light so that Block knew exactly where each bead was.
But in dealing with such small objects, he could not afford any of the normal wobbles in the light that occur when the photons have to pass through different densities of air at differing temperatures. So, he encased the whole microscope in a box containing helium. Helium has a very low refractive index so, even if temperature fluctuations occurred, the effect would be too small to matter.
One by one
The group then manipulated one of the glass beads until the RNAP latched on to a rung on the DNA molecule. As the enzyme moved along the bases, it tugged the glass bead it was bonded too, moving the two beads toward each together. The RNAP jerked along the DNA, pausing between jerks to churn out RNA transcribed bases. It was by precisely measuring the lengths of the jerks that Block determined how many bases it transcribed each time.
“The RNAP climbs the DNA ladder one base pair at a time – that is probably the right answer,” he says.
“It’s a very neat system – amazing to be able see molecular details and work out how DNA is transcribed for the first time,” said Justin Molloy, who has pioneered similar work at the National Institute for Medical Research, London. “It’s pretty incredible. You would never have believed it could be possible 10 years ago.”
Journal reference: Nature (DOI: 10.1038/nature04268)
That book contains infinate layers of proof that it was fully inspired by God. Some of the proofs are logical, such as fulfillment of prophecy, but the greatest bulk lies in complex patterns, mostly with a numeric basis.
"Sin all you want to...well make more ( forgiveness)"
Doesn't work that way. Once you're his, you won't want to sin.
"Sure, tyranny in action right?"
Do you spend a lot of time shouting at umpires? He made the universe, he made us, he provided the path to eternal life at no cost to us; where's the tyranny in sluffing off those who reject his love and free gift?
"just like "1984," it is a warning."
I meant the doublespeak. :)
Man, you've read my posts and responded to them, yet you look for evidence of intelligent design. Go figure. Is it because it's cyberpace that you think the evidence is not physical? Do you think a ghost is writing on my behalf? I'm here to tell you it ain't Lurch.
" How does anyone look at the wonder of DNA and think "accident" and "random chance"?"
My thoughts exactly. There is no way in my mind that this process could have developed purely by chance.
"Yes, doublespeak, or the concept of holding two contradictory ideas in one's mind and accepting both of them at the same time, was meant as a warning by G. Orwell."
Like the idea that Vengeance is Mercy.
does not seem to me to fulfill the rules of evidence required elsewhere on this thread. :-)
Cheers!
Am I crazy here or are we actually making strides toward something like this?
A number of years back researchers at one of the IBM labs manipulated individual atoms to spell out the letters IBM
The manipulation of individual atoms isn't necessarily the problem; it is rather the sheer NUMBER of atoms which have to be processed in order to have any macroscopic structural effects.
Cheers!
The Creator has made known that His "power is made pefect in weakness." How Orwellian is that?
"The Creator has made known that His "power is made pefect in weakness." How Orwellian is that?"
What does that mean?
Reminds me of CO and pi backbonding :-)
Cheers!
"Double Plus Ungood" ??
In other words, "If you can put God on display for direct observation, I'd like to see Him."
You ass.
That's nice, but it's hardly scientific.
You have an emotional response to something, and actually equate that with physical evidence?
Wow. That's the best indictment of "ID is science" that I've seen so far. Thanks.
Let's see. Maybe I can put a black hole in front of you, too, so you can know they exist without making inferences.
Why should an "argument from incredulity" be considered a bad argument?
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